Modern consumer rear-screen projection televisions utilize liquid coupling of the projection optics to the CRT faceplates to enhance contrast and to avoid localized hot spots on the CRT which may result in CRT failure. The coupling is accomplished by way of a metal coupler (either die cast or stamped) which has a special coating to provide a surface durable enough to withstand the corrosive nature of the coupling fluid, e.g., a mixture of ethylene glycol and glycerine.
The metal coupler is a significant cost component in the overall television set. An example of such a prior art coupler, composed of die-cast aluminum and comprising multiple cooling fins and an integral expansion chamber, is shown in FIG. 2 of Hanyu et al., U.S. Pat. No. 5,010,396.
In the past, attempts have been made to cost-reduce the system by molding the coupler from plastic resins and protecting the coupler body from the coupling fluid by adding a rubber bladder inside the coupler housing. This system has not been commercially successful. Possible reasons for this include cost of the bladder, reliability/life of the bladder, poor thermal conductivity through the bladder/housing, thermal degradation of the bladder and/or coupler, and lack of x-ray absorption (another function of the metal couplers).
The present invention is directed at solving these problems associated with the use of plastic materials in couplers.